Whether listening to sound from a portable media player while traveling or from a theater system while at home, consumers often use headphones rather than open air loudspeakers to do so. Some headphones include at least one earpiece with a driver for emitting sound waves and an eartip communicatively coupled to the driver and insertable into a user's ear canal for directing the sound waves from the driver and through the user's ear canal towards the user's eardrum. When such headphones are worn by a user, the eartip may deform in order to fit inside the user's ear canal. However, such eartips are often unable to obtain or maintain a deformed shape that substantially matches the unique shape of a particular user's ear canal in order to create an efficient acoustic seal. Accordingly, alternative eartips for earpieces are needed.